re PR middle-end/23488 (GCSE load PRE does not work with non sets (or missing load PRE with plain decls))

2007-07-06  Daniel Berlin  <dberlin@dberlin.org>

	Fix PR tree-optimization/23488

	* tree-ssa-sccvn.c (expr_has_constants): Handle tcc_declaration.
	(try_to_simplify): Ditto.
	(visit_use): Ditto.
	* tree-vn.c (set_value_handle): Use decl_vh_map for decl value
	handles.
	* tree-flow-inline.h (get_value_handle): Ditto.
	* tree-ssa-pre.c (decl_vh_map): New.
	(decl_node_pool): New.
	(can_value_number_operation): Support DECL_P.
	(can_PRE_operation): Ditto.
	(create_expression_by_pieces): Ditto.
	(find_existing_value_expr): Modify to differnetiate between
	addressing and top level.
	(create_value_handle_for_expr): Handle DECL's.
	(poolify_tree): Ditto.
	(make_values_for_phi): Don't insert into PHI_GEN during FRE.
	(make_values_for_stmt): Handle DECL's properly.
	(init_pre): Reorg to not init useless things during FRE.
	(fini_pre): Ditto.
	* tree-flow.h: Include pointer-set.h.
	(decl_vh_map): Declare.
	* Makefile.in (TREE_FLOW_H): Add pointer-set.h

From-SVN: r126434